1. Technical Field
The disclosure generally relates to centrifugal fans and, more particularly, to an electronic device incorporating a centrifugal fan for dissipating heat generated therefrom.
2. Description of Related Art
With the fast development of the electronics industry, electronic components, such as central processing units (CPUs), or video graphics array (VGA) chips, are being made with ever faster operating speeds. During operation of the electronic components, a large amount of heat is generated. Greater emphasis is now being laid on increasing the efficiency and effectiveness of heat dissipation devices so as to keep operational temperature of the electronic components within a suitable range.
Conventionally, a fan is used in combination with a heat dissipation device to produce an airflow in order to remove heat from the electronic components. Since most of electronic systems that contain electronic components therein, such as a laptop computer or a desktop computer, do not have enough space therein, a centrifugal fan which requires only a small space for installation is generally used. The centrifugal fan has at least an air inlet and an air outlet oriented perpendicularly to the at least an air inlet. In use, the centrifugal fan generates an airflow from the at least an air inlet towards the electronic component via the air outlet, thus cooling the electronic component continuously.
The diameter of the at least an air inlet is smaller than the diameter of an impeller of the centrifugal fan. For avoiding friction between the impeller and a housing of the centrifugal fan, an axial clearance must be defined between the housing and the impeller, which conflicts with the requirement that the centrifugal fan can only occupy a small space in the electronic system. Additionally, due to the presence of the clearance, portion of the airflow flows back to the at least an air inlet via the clearance directly, thus to cause air turbulence at the least an air inlet and decrease air pressure in the centrifugal fan.
Therefore, there is a need for a centrifugal fan, which can eliminate the limitations described.